Revert "Revert "releasetools: Allow using futility-host to sign old TF.zip."" am: 77620b5a45 am: 9eea2cde67 am: 8fa3351890 am: dce7c28f7c am: 869793b198
am: ab8422e34a

Change-Id: I16f5fb054573428a12f8f454e014247dd0316e3a